5 files changed, 227 insertions, 0 deletions
diff --git a/src/marlin.core/models/plan/CommandResult.cs b/src/marlin.core/models/plan/CommandResult.cs
new file mode 100644
index 0000000..3385e84
--- /dev/null
+++ b/src/marlin.core/models/plan/CommandResult.cs
@@ -0,0 +1,17 @@
+namespace marlin.core.models.plan;
+
+[Flags]
+public enum CommandResult : byte
+{
+    Success = 1,
+    Failure = 2,
+    Unconditional = Success | Failure,
+}
+
+public static class CommandResultExtensions
+{
+    public static bool Matches(this CommandResult self, CommandResult contains)
+    {
+        return (self & contains) != 0;
+    }
+}
+\ No newline at end of file
diff --git a/src/marlin.core/models/plan/CommandResultSelector.cs b/src/marlin.core/models/plan/CommandResultSelector.cs
new file mode 100644
index 0000000..92c41c7
--- /dev/null
+++ b/src/marlin.core/models/plan/CommandResultSelector.cs
@@ -0,0 +1,13 @@
+namespace marlin.core.models.plan;
+
+public class CommandResultSelector
+{
+    public ExecutionCommand Command { get; }
+    public CommandResult Result { get; }
+
+    public CommandResultSelector(ExecutionCommand command, CommandResult result)
+    {
+        this.Command = command;
+        this.Result = result;
+    }
+}
+\ No newline at end of file
diff --git a/src/marlin.core/models/plan/CommandRole.cs b/src/marlin.core/models/plan/CommandRole.cs
new file mode 100644
index 0000000..8005532
--- /dev/null
+++ b/src/marlin.core/models/plan/CommandRole.cs
@@ -0,0 +1,8 @@
+namespace marlin.core.models.plan;
+
+public enum CommandRole
+{
+    Step = 0,
+    ArtifactHandler = 1,
+    Cleanup = 2
+}
+\ No newline at end of file
diff --git a/src/marlin.core/models/plan/ExecutionCommand.cs b/src/marlin.core/models/plan/ExecutionCommand.cs
new file mode 100644
index 0000000..124da63
--- /dev/null
+++ b/src/marlin.core/models/plan/ExecutionCommand.cs
@@ -0,0 +1,15 @@
+namespace marlin.core.models.plan;
+
+using meta;
+
+public class ExecutionCommand
+{
+    public required string Id;
+    public required string Name;
+    public required string Command;
+    public required CommandRole Role;
+    public required bool Deferred;
+    public CommandResultSelector? ResultSelector;
+    
+    public required FailBehavior FailBehavior;
+}
+\ No newline at end of file
diff --git a/src/marlin.core/models/plan/ExecutionPlan.cs b/src/marlin.core/models/plan/ExecutionPlan.cs
new file mode 100644
index 0000000..24c40e4
--- /dev/null
+++ b/src/marlin.core/models/plan/ExecutionPlan.cs
@@ -0,0 +1,174 @@
+namespace marlin.core.models.plan;
+
+using meta;
+using util;
+
+public class ExecutionPlan
+{
+    public IEnumerable<ExecutionCommand> Components => [..this._commands, ..this._deferredArtifactHandler, ..this._deferredCleanup];
+
+    private readonly List<ExecutionCommand> _commands;
+    private readonly List<ExecutionCommand> _deferredArtifactHandler;
+    private readonly List<ExecutionCommand> _deferredCleanup;
+
+    public ExecutionPlan()
+    {
+        this._commands = new();
+        this._deferredArtifactHandler = new();
+        this._deferredCleanup = new();
+    }
+
+    private void AddCommand(ExecutionCommand command)
+    {
+        if (!command.Deferred)
+            this._commands.Add(command);
+
+        else
+        {
+            switch (command.Role)
+            {
+                case CommandRole.Cleanup:
+                    this._deferredCleanup.Add(command);
+                    break;
+
+                case CommandRole.ArtifactHandler:
+                    this._deferredArtifactHandler.Add(command);
+                    break;
+
+                default:
+                    throw new InvalidOperationException($"Cannot defer {command.Role}");
+            }
+        }
+    }
+
+    public static ExecutionPlan Create(Workflow workflow, Recipe recipe)
+    {
+        ExecutionPlan plan = new();
+
+        AddToExecutionPlan(plan, workflow, recipe, null);
+
+        return plan;
+    }
+
+    private static ExecutionCommand? AddToExecutionPlan(ExecutionPlan plan, Workflow workflow, Recipe recipe, ExecutionCommand? previousCommand)
+    {
+        foreach (var dependentRecipe in recipe.GetRequires(workflow))
+            previousCommand = AddToExecutionPlan(plan, workflow, dependentRecipe, previousCommand);
+
+        Dictionary<string, string> recipeArgs = recipe.CreateArguments();
+
+        foreach (var step in recipe.Steps.Values)
+        {
+            var command = CreateCommand(step, recipe, workflow, false, recipeArgs, out var commandArgs);
+            if (previousCommand != null)
+            {
+                command.ResultSelector = new CommandResultSelector(previousCommand,
+                    previousCommand.FailBehavior switch
+                    {
+                        FailBehavior.Continue => CommandResult.Unconditional,
+                        FailBehavior.Stop => CommandResult.Success,
+                        FailBehavior.StopAfter => CommandResult.Success,
+
+                        _ => throw new ArgumentOutOfRangeException()
+                    });
+            }
+
+            plan.AddCommand(command);
+
+            var cleanupCommand = CreateCleanupCommand(step, command, recipe, workflow, commandArgs);
+            if (cleanupCommand != null)
+                plan.AddCommand(cleanupCommand);
+
+            previousCommand = command;
+        }
+
+        return previousCommand;
+    }
+
+    private static ExecutionCommand CreateCommand(
+        AbstractStep step,
+        Recipe recipe,
+        Workflow workflow,
+        bool defer,
+        Dictionary<string, string> baseArgs,
+        out Dictionary<string, string> createdArgs)
+    {
+        string? name = null;
+        string? run = null;
+        FailBehavior? fail = null;
+
+        Dictionary<string, string> args = new(baseArgs);
+
+        foreach (var stepHierarchy in step.GetAncestorsAndThis(workflow))
+        {
+            name ??= stepHierarchy.Name;
+            run ??= stepHierarchy.Run;
+            fail ??= stepHierarchy.Fail;
+
+            foreach (var kvp in stepHierarchy.With)
+                args.TryAdd(kvp.Key, kvp.Value);
+        }
+
+        name ??= step.Id;
+        fail ??= FailBehavior.Stop;
+
+        if (run == null)
+            throw new Exception($"No run found for {recipe.Name}.{name}");
+
+        run = VariableExpander.Expand(run, args);
+
+        ExecutionCommand stepCommand = new ExecutionCommand
+        {
+            Id = step.Id,
+            Name = name,
+            Command = run,
+            Role = step switch
+            {
+                ArtifactHandlerStep => CommandRole.ArtifactHandler,
+                RecipeStep => CommandRole.Step,
+                CleanupStep => CommandRole.Cleanup,
+                _ => throw new ArgumentOutOfRangeException()
+            },
+            FailBehavior = fail.Value,
+            Deferred = defer
+        };
+
+        createdArgs = args;
+        return stepCommand;
+    }
+
+    private static ExecutionCommand? CreateCleanupCommand(RecipeStep parentStep,
+        ExecutionCommand parentCommand,
+        Recipe recipe,
+        Workflow workflow,
+        Dictionary<string, string> baseArgs)
+    {
+        var cleanupStep = GetCleanup(parentStep, workflow);
+        if (cleanupStep == null)
+            return null;
+
+        var cleanupCommand = CreateCommand(cleanupStep, recipe, workflow,
+            cleanupStep.After == CleanupAfter.Recipe, baseArgs, out _);
+
+        cleanupCommand.ResultSelector = new CommandResultSelector(parentCommand,
+            parentCommand.FailBehavior switch
+            {
+                FailBehavior.Stop => CommandResult.Success,
+                FailBehavior.StopAfter => CommandResult.Unconditional,
+                FailBehavior.Continue => CommandResult.Unconditional,
+
+                _ => throw new ArgumentOutOfRangeException()
+            });
+
+        return cleanupCommand;
+    }
+
+    private static CleanupStep? GetCleanup(RecipeStep step, Workflow workflow)
+    {
+        return step
+            .GetAncestorsAndThis(workflow)
+            .OfType<RecipeStep>()
+            .Select(x => x.Cleanup)
+            .FirstOrDefault(x => x != null);
+    }
+}